How Far Away are Galaxies?

Well, I’ll give you a spoiler: they’re ridiculously far away.

Let’s consider for a moment what a light-year actually means. It sounds like a unit of time, but it’s actually the distance that light travels in one Earth year.

Think of it this way: if your name is Bob, and you can travel a certain distance in one year, that distance could be called a Bob-year.

I know it’s strange to think of light traveling at a certain speed. When you flip a light switch, the room immediately brightens. When you shine a flashlight, its beam immediately falls across the nearest surface.

But that just goes to show how insanely fast light travels. If it takes 2 million years for light to get from one object to another…imagine how far apart those objects are?

Well, that’s the case for our home galaxy, the Milky Way, and our nearest galactic neighbor, the Andromeda Galaxy.

But…wait a second. How do we know that?

Continue reading

The Different Shapes of Galaxies

By now, we’ve spent a heck of a lot of time exploring spiral galaxies.

It makes sense–they’re certainly the most photogenic. Seriously. Do me a favor and do a quick Google search for galaxies. When I did, nearly all the results were spirals…even though spirals are not the most common galaxies in the universe.

There is, of course, another reason we’re so familiar with spirals right now. We dipped our toes in the waters of studying galaxies by exploring our own home galaxy–a reasonable starting point. Our Milky Way just happens to be a spiral.

Well…it doesn’t “just happen” to be a spiral. But we’ll get to the reasons for that…

For now, let’s take a dive into all the different types of galaxies.

Continue reading

A Universe of Galaxies

When the earliest astronomers and philosophers looked up at the night sky, they never could have imagined a sight like this.

What if I told you there are only four single stars in this image?

That’s right. Four.

The rest are whole galaxies, full of billions of stars.

You can tell the foreground stars from the galaxies by the diffraction spikes–astronomer speak for those four bright spikes of light. Can you find them?

Continue reading